This new release brings much faster dynamic predicates, prolog flags to deal with them, and a few improvements due to customer requests which we gratefully acknowledge. CORBA was added into the set of provided extensions.

Notes:

1. *.mbc MINERVA binary code is not compatible to previous releases of MINERVA. Please recompile *.min source files to update your *.mbc binary code files.
2. *.min MINERVA source programs are upward compatible.
3. Please update your *.msp and *.mca MINERVA Startup Property and Compressed Archives if you are using custom files that access MINERVA libraries.
4. This version executes on Java 1.1 and on Java 1.2. (Caution: Netscape 4.0.4 and earlier do not suffice.)

New Functionality:

1. Fast Dynamic Predicates

   Dynamic predicates (see dynamic, asserta, assertz, retract) are now implemented with smart indexing. Customer applications which make heavy use of dynamic predicates showed a performance increase of two orders of magnitude over previous versions of MINERVA.

   A word about indexing in MINERVA: indexing is a general word for a variety of methods to increase access speed to collections of data from linear resp exponential to constant resp logarithmic time. In MINERVA there are 3 forms of data: compiled predicates, dynamic predicates, and blackboards.

   For compiled predicates, "first argument indexing" is used for collections of predicates where the first argument is not a variable. Indexing works on the functor and arity of the predicate and the functor of the first argument, deeper parts of a term are not used.

   For dynamic predicates, "smart indexing" is done whenever MINERVA considers it worthwhile over all arguments which are never asserted as a variable. Indexing works on the functor and arity of the predicate and the functor of the targeted arguments, deeper parts of a term are not used.

   For data stored in blackboards, "exhaustive indexing" is done over the key: the whole term, incuding its deeper parts, is used as material for indexing.

   Programming Hints:

   1) Indexing can only be performed for data sets that are "ground" i.e. not variables in the important locations. Indexing something like:

   		a(1).
   		a(2).
   		a(X) :- X = undetermined.  % catch-all case
   	

   will NOT result in the desired speedup. This is a BAD example.

   2) Access to indexed data sets is only fast if the key is actually used. Compare:

   	Data:
   		male(eric).
   		male(kentaro).
   			:
   		female(mika).
   		female(sonya).
   			:
   	Program:
   		% GOOD			% BAD
   		?- male(charles).	?- male(X), X = kaori.
   	

2. prolog_flags MINERVA 2.1 knows set_prolog_flag/2 and get_prolog_flag/2:

   set_prolog_flag knows 'unknown' with possible values error, warning and fail.

   get_prolog_flag knows 'max_arity' and 'unknown'.

   In violation of the ISO Standard for Prolog, the first argument to get_prolog_flag must be instantiated.

3. predicate_type/2 predicate_type/2 returns dynamic, static, or undefined.

4. improved sort/2

   Upon a customer complaint the implementation of sort/2 was replaced with a highly efficient and better behaved version.

5. CORBA in ExamplePrograms/Extensions

   Upon request we added the source and precompiled MINERVA predicates to access CORBA. See ExamplePrograms/Extensions/CORBA/

Please also re-read the Release Notes of previous versions of MINERVA. You have feedback on this release or requests for the next? Please let us know!

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